Architectural acoustics
Architectural acoustics is the science of noise control within buildings. The first application of architectural acoustics was in the design of opera houses and then concert halls. More widely, noise suppression is critical in the design of multi-unit dwellings and business premises that generate significant noise, including music venues like bars. The more mundane design of workplaces has implications for noise health effects. Architectural acoustics includes room acoustics, the design of recording and broadcast studios, home theaters, and listening rooms for media playback. Building skin envelope This science analyzes noise transmission from building exterior envelope to interior and vice versa. The main noise paths are roofs, eaves, walls, windows, door and penetrations. Sufficient control ensures space functionality and is often required based on building use and local municipal codes. An example would be providing a suitable design for a home which is to be constructed close to a high volume roadway, or under the flight path of a major airport, or of the airport itself. Inter-space noise control The science of limiting and/or controlling noise transmission from one building space to another to ensure space functionality and speech privacy. The typical sound paths are room partitions, acoustic ceiling panels (such as wood dropped ceiling panels), doors, windows, flanking, ducting and other penetrations. An example would be providing suitable party wall design in an apartment complex to minimise the mutual disturbance due to noise by residents in adjacent apartments. Interior space acoustics This is the science of controlling a room's surfaces based on sound absorbing and reflecting properties. Excessive reverberation time, which can be calculated, can lead to poor speech intelligibility. Sound reflections create standing waves that produce natural resonances that can be heard as a pleasant sensation or an annoying one.Glen Ballou & Howards Sams, editors. "Handbook for Sound Engineers", page 56. Reflective surfaces can be angled and coordinated to provide good coverage of sound for a listener in a concert hall or music recital space. To illustrate this concept consider the difference between a modern large office meeting room or lecture theater and a traditional classroom with all hard surfaces. Interior building surfaces can be constructed of many different materials and finishes. Ideal acoustical panels are those without a face or finish material that interferes with the acoustical infill or substrate. Fabric covered panels are one way to heighten acoustical absorption. Finish material is used to cover over the acoustical substrate. Mineral fiber board, or Micore, is a commonly used acoustical substrate. Finish materials often consist of fabric, wood or acoustical tile. Fabric can be wrapped around substrates to create what is referred to as a "pre-fabricated panel" and often provides the good noise absorption if laid onto a wall. Prefabricated panels are limited to the size of the substrate ranging from 2'x 4' to 4' x 10'. Fabric retained in a wall-mounted perimeter track system, is referred to as "on-site acoustical wall panels" This is constructed by framing the perimeter track into shape, infilling the acoustical substrate and then stretching and tucking the fabric into the perimeter frame system. On-site wall panels can be constructed to accommodate door frames, baseboard, or any other intrusion. Large panels (generally, greater than 50 square feet) can be created on walls and ceilings with this method. Wood finishes can consist of punched or routed slots and provide a natural look to the interior space, although acoustical absorption may not be great. There are three ways to improve workplace acoustics and solve workplace sound problems – the ABCs. *A = Absorb {via drapes, carpets, ceiling tiles, etc.) *B = Block (via panels, walls, floors, ceilings and layout) *C = Cover-up (via sound masking) While all three of these are recommended to achieve optimal results, C = Cover-up by increasing background sound produces the most dramatic improvement in speech privacy – with the least disruption and typically the lowest cost. Mechanical equipment noise Building services noise control is the science of controlling noise produced by: *ACMV (air conditioning and mechanical ventilation) systems in buildings, termed HVAC in North America *Elevators *Electrical generators positioned within or attached to a building *Any other building service infrastructure component that emits sound. Inadequate control may lead to elevated sound levels within the space which can be annoying and reduce speech intelligibility. Typical improvements are vibration isolation of mechanical equipment, and sound traps in ductwork. Sound masking can also be created by adjusting HVAC noise to a predetermined level. See also *Noise mitigation *Noise Reduction Coefficient *Noise regulation *Noise, vibration, and harshness *Room acoustics *Sound transmission class References External links *Acoustical Society of America *American Institute of Architects *National Council of Acoustical Consultants *Institute of Acoustics *Speech Privacy Calculator *diracdelta.co.uk Room mode calculator *An on-line version of an exhibition on concert hall acoustics originally shown at the South Bank Centre, London *Aural Architecture *WikiRecording's Guide to Recording Studio Acoustics *Acoustic Modelling using Google SketchUp *Concert Hall Acoustics *Concert Hall Acoustics *Everything You Always Wanted to Know About Concert Hall Acoustics Category:Acoustics Category:Building engineering Acoustic problems